The present invention relates to a method and device for selecting an IP address of a UE.
In general, a User Equipment (UE) receives an allocation of an IP address for a wireless communication interface from a network (for example, a cellular network such as Long Term Evolution (LTE) or a wireless local area communication network (Wireless LAN)) and performs communication using the allocated IP address. For example, the UE may receive an allocation of IP addresses from a gateway of the cellular network and/or Access Point (AP) of the WLAN and perform a service requested by the user using the allocated IP address.
Recently, when the plurality of IP addresses are allocated to the UE, a scheme for selecting an effective IP address among the allocated plurality of IP addresses has been studied. For example, since the size of an area managed by a corresponding network node may be different and a path for connecting each service may be different for each IP address, a scheme has been studied for selecting, by the UE, an IP address which can provide a service requested by the user in a stable manner without discontinuation. For example, in 3GPP release 10, when IP addresses are allocated from different network nodes such that a network node (for example, a gateway) located closest to the location of the UE is selected and an allocation of a new IP address is received from the network node so as to perform the communication with an external network (for example, the Internet), a Selective IP Traffic Offload (SIPTO) technique is provided such that IP addresses allocated from the network node located closest to the location of the UE are selected to enable the UE to perform the communication with the external network (for example, the Internet) through a network node (for example, the gateway) located closest to an access network. For another example, for a UE supporting both a cellular network and a WLAN, a technique has been provided which allows the communication using an IP address allocated from an AP of the WLAN after cutting off the communication with the cellular network when the UE is connected to the WLAN. However, the conventional gateway/network selection techniques may cause a change in the IP address so that it is difficult to guarantee the continuity of the service or performance experienced by the user for the service used by the UE.